'The method of observing with the Altazimuth is carefully described, and the effect of it, in increasing the number of observations of the Moon, is thus given for the thirteen lunations between 1847, May 15, and 1848, May 30.

As the siege and war operations in Paris seriously interfered with the observations of small planets made at the Paris Observatory, observations of them were continued at Greenwich throughout each entire lunation during the investment of the city.

Observations were made during portions of three lunations of the transit of the moon's bright limb and of such tabulated stars as differed but little in right ascension and declination from the moon, in order to obtain additional data to those furnished by chronometrical comparisons with the meridian of Boston for computing the longitude of this meridian line.